Blackjack

Provably fair

Verify fairness

The session's seed decides every card. Its hash was committed before the first hand; the seed is revealed when the session ends. Each round's cards come from HMAC-SHA256 keyed by the seed over the round's number and the bettor's own seed.

Seed hash

93ca70eb7c91ce02e5c8a4048993b6556fc529d7bb4c3942539153897c709a38

Seed

e4270eff100655c1be7c9dfe75689c11a89d297c381cf2115659e6fcaa2d253b SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

3595121af70188a00c6eb8f50d20926d

Commitment

Batch 72,808, Merkle root fbbf149f16bb09104af1db6766d681f245271381a5ce41b98883891e035cc504. Recorded by Degen Protocol; on-chain publication is not available yet. See this batch and its Merkle tree

Merkle path

1. d12d42c84bc36bcd0a34558e38e12d2b69fdabdd597a56ce7ff78819d388ed0c
2. ca42ec31deff4531022f88534f1b6d5bc26bdfa432fb75f20b6c31976f0ad5cc
3. 26292befdb4d36111cc29b5245e43c71c665910f66ef13f3ca0b0ed65bb1ae91

Checked: the seed hash proves into the root.

To check it yourself, take the session's proof:

1. Hash the seed as above and compare it with the seed hash; prove the seed hash into the root with the Merkle path (keccak256, as for every match).
2. For each round: round seed = HMAC-SHA256(key = seed, "degen.house.round.v1" ‖ 0x00 ‖ u64be(length of the bettor's seed) ‖ bettor's seed ‖ u64be(round)).
3. Key ChaCha20 (RFC 8439, zero nonce) with the round seed and read little-endian 64-bit words; a card is the next word below 2⁶⁴ − 1 − ((2⁶⁴ − 1) mod 52), modulo 52.
4. Replay the round's actions with the game's rules: the cards and the payout must match.

The replay plays every hand rebuilt this way on the server from the same data, and marks any that does not rebuild as recorded.